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  International web site Geosynthetics Drainage DRAINAGE OF TUNNELS AND UNDERGROUND STRUCTURES  
drainage of tunnels and underground structures drenaggio di gallerie e strutture interrate drenaje de tuneles y estructuras subterraneas Drainage de tunnels et de structures enterrées
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Drainage of tunnels and underground structures


installation of Tenax geocomposite
Installation of TENAX TDP

installation of Tenax Geocomposite on the tunnel face
Installation of TENAX TDP
Geocomposite on the tunnel face




During the construction of underground concrete lined structures (tunnels in particular), it is necessary to prevent water from coming into contact with the completed tunnel lining that can cause both safety problems and increased maintenance costs.

The use of TENAX MDP geocomposite, specified for the interception and drainage of water inflows (even when under pressure), which inevitably tend to flow towards the excavation site, gives a uniform surface upon which the sprayed concrete is applied thereby reducing installation costs and giving a higher degree of impermeability.

The geocomposite also functions as a "left in place formwork", in addition to limiting the volume of concrete used, it allows for construction to proceed in accordance with the assumptions made during the planning stage thus allowing:

  • Constant thickness of finished reinforced concrete structures;
  • Uniformly distributed loads (even under point loads) and thus constant long-term hydraulic flow rates even when under considerable pressure;
  • Reduced shearing stress that could otherwise totally burden the structure;
  • Limited load transmission (even under dynamic loads) which can be caused by settlements and/or spreading deformations of the surrounding areas (the geocomposite acts as a semi-flexible element placed between the trench surface and the final structure).

If the need for an additional impermeable layer is foreseen, the TENAX MDP geocomposite will protect it from rock puncturing, damages caused by microorganisms and from particularly corrosive soils, thus preserving the finished structure from rapid degradation.






TENAX MDP geocomposite (geomembrane + geonet + geotextile)

TENAX TDP geocomposite (geotextile + cuspated geonet)





complete installation of the geocomposite prior to shotcreting


Completed installation of TENAX TDP geocomposite prior to shotcreting. This system offers substantial savings over traditional methods.





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